Borty77 the pyrodex could be what is causing your problems. I would only shoot a pure black powder like Goex in a Flintlock. Pyrodex although does work will take a lot more spark to fire. I am wondering if your ignition seems like it takes for ever to take off?

Run an alcohol patch or two down the barrel then two dry ones before you load. Also wipe the frizzen, flint off, and pan out with the same alcohol patch then load it with some Goex and see if that is not the cure to your problems. I was shooting 90 grains of Goex FFg and moose milk patched roundball out of my T/C Hawkins the other day. It was really a good time and the ignition is really fast with black english flints.....